JP2000030402A - Leaf spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide leaf springs which lessen the occurrence of clinging by overlapping of the plural leaf springs on each other at the time of transporting, storing or automatic assembling of the approximately U-shaped leaf springs, allow the easy removal of the overlaps in spite of partial overlaps on each other and maintain urging force in a specified range. SOLUTION: This approximately U-shaped leaf 1 has a central curved part 3, arm parts 5a, 5b which extend approximately to a chevron shape on both right and left sides of the central curved part 3, curved parts 13a, 13b which are curved and are connected to both ends of these arm parts 5a, 5b and leg parts 7a, 7b which have curved parts 15a, 15b which are extended from the curved parts 13a, 13b and are curved toward the outer side at their terminals. The leg parts 7a, 7b are so formed as to exist on the plane passing the beginning ends of the leg parts 7a, 7b parallel with the central plane of the approximately U-shaped leaf 1 or on the side outer than the plane. The curved parts 13a, 13b of the leg parts 7a, 7b are curved to the inner side with respect to the arm parts 5a, 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a leaf spring.

[0002]

2. Description of the Related Art In a product comprising various components, various coil springs and leaf springs are used to urge components that perform various operations such as opening and closing, rotation, engagement, sliding, and sliding contact in a predetermined direction. Is used. For example, DA is known as a recording medium for recording digital signals on a magnetic tape at high density.
As shown in FIG. 3, a magnetic tape cassette such as T, DDS or the like includes an upper half 50, a lower half 52 coupled to the upper half 50 to form a case body, and arrows A along the bottom and side surfaces of the lower half 52. And a slider 54 that is slidably fitted in the direction, and accommodates the magnetic tape in the case body. In this magnetic tape cassette, when the magnetic tape is not used, the slider 54 is attached to the lower half 5.
2 is a slider spring composed of a coil spring, a leaf spring, etc. (in the magnetic tape cassette shown in the drawing, approximately U
The slider is biased forward by a slider spring 56) formed of a U-shaped leaf spring.

As shown in FIG. 5, a leaf spring used as a slider spring 56 in the magnetic tape cassette shown in FIG. Pair of arms 74a and 74 extending to
b, and a pair of legs 76a and 76b formed at both ends of the arms 74a and 74b. In the slider spring 56 composed of this leaf spring, the central bent portion 72 is mounted on a slider spring engaging portion 86 provided at the center of the front edge of the lower half. Also, legs 7
6a and 76b are outwardly curved sliding contact portions 82a that abut against an abutting wall 80 erected at the front end of the slider 54.
And 82b. When the magnetic tape is used, the slider spring 56 slides the slider 54 back and forth, and the sliding portions 82a and 82b slide outward on the contact wall 80, respectively, so that the two arm portions 74a and 74b When the slider 54 slides forward, the slider 54 is urged forward toward the inner end of the front lid 60.

A slider spring 56 in a magnetic tape cassette having such a slider 54
It is required that the urging force always falls within an appropriate range, for example, 15 g to 150 g without suddenly changing the urging force when the vehicle moves forward and backward. For this reason, as shown in FIG. 6, when the two arms 74a and 74b of the slider spring 56 are opened by the retreat of the slider 54, the two arms 74a and 74b are closed.
The legs 76a and 76b are provided with substantially U-shaped slider springs 56 so that the surface 4b does not come into surface contact with the contact wall 80.
Has a projection whose inside is convex. If there are no convex projections, the arms 74a and 74b will be in surface contact with the abutment wall 80, and the substantial length of the spring-acting portions of the arms 74a and 74b will be reduced. Spring 56
This is because the repulsive force of the slider 54 sharply increases, and as a result, the urging force applied to the slider 54 sharply increases. In addition, as proposed in Japanese Utility Model Publication No. 4-45185, the sliding contact portion of the slider spring is formed in a semicircular projection shape facing inward of a substantially U-shape, so that both arm portions are formed. The surface contact with the contact wall is prevented, and the sudden increase in the urging force applied to the slider is suppressed.

[0005] This substantially U-shaped slider spring 56 is shown in FIG.
In the magnetic tape cassette shown in FIG. 5, the lower half 52 is assembled from the upper surface side of the lower half to a slider spring engaging portion 86 which opens upward at the center of the front edge. Further, in the magnetic tape cassette having the lower half 84 shown in FIG. 4, the slider spring 56 is attached to the slider spring engaging portion 78 which is provided to open downward at the center of the front edge of the lower half 84 from the bottom side of the lower half. Assembled.

A leaf spring represented by this slider spring is:
Usually, it is manufactured from a plate material by a forming process such as a punching press process and a bending process, and is stored, transported, and supplied to an assembly process. These leaf springs, with dozens of them stacked,
Alternatively, they are supplied to an automatic assembly line in a state where they are stacked and loaded in a magazine, and then separated one by one by a parts feeder or, if necessary, a separator (balancing machine) and supplied to an automatic assembling apparatus. For example, in an automatic assembly line for magnetic tape cassettes, several tens of
Alternatively, the slider springs supplied in a state of being stacked and loaded in a magazine are separated and aligned one by one by a parts feeder or a separator (balancing machine) as necessary, and the separated parts are supplied to an automatic assembling apparatus. Thus, the lower half is attached to the slider spring engaging portion.

[0007]

However, since the above-mentioned substantially U-shaped leaf springs have a small thickness, they are sometimes overlapped and overlaid. For example, as shown in FIG. 7, in the conventional leaf spring 88, a portion where the bent portions 92a or 92b of the two leg portions 90a or 90b overlap (portions indicated by A and B in FIG. 7) occurs. In some cases, a phenomenon that a portion (a portion indicated by C and D in FIG. 7) overlapping a portion near the straight line of the both arms 94a or 94b occurs, a phenomenon called so-called hugging may occur. It was difficult to separate the leaf springs having such a hug by a parts feeder or a separator.

Further, when this type of leaf spring is assembled by an automatic assembling apparatus, the front and rear leaf springs overlap when feeding and aligning with a parts feeder because the wall thickness is thin. Supply to the system sometimes became inconvenient. For example, as shown in FIG. 8 (a), in the case of sequentially feeding in the direction of arrow E using a straight-type parts feeder or the like, the front and rear leaf springs 9 are pushed when pressed in the direction of arrow E.
In some cases, 3a and 93b overlap as shown in FIG. 8 (b).

To solve such a problem, Japanese Utility Model Registration No. 2551203 discloses a shape of a leaf spring for preventing the leaf springs from overlapping as shown in FIG. . The shape of the leaf spring includes a notched annular portion in which a part of an annular body is cut out, and a pair of arms extending in a C shape from both ends of the notched annular portion. The space between both ends is smaller than the maximum diameter of the notched annular portion. Then, by adopting this shape, as shown in FIG.
When a large number of leaf springs are aligned, no clinging or overlapping occurs, and the assemblability is effectively improved.
However, since the slider spring has a small wall pressure, when it is pushed in the direction of arrow E by a parts feeder as shown in FIG.
As shown in FIG. 8B, the front and rear leaf springs sometimes overlap. In that case, since the interval between the cut ends of the cutout annular portion is smaller than the maximum diameter of the cutout annular portion, the only way to separate the overlapping leaf springs is to pull out the leaf springs in the plate width direction, Because the pulling direction is limited,
The current situation is that the efficiency of assembly work does not increase. Further, since it is necessary to store the slider spring in the limited space of the lower half 52, as shown in FIG.
It is difficult to make the plane shape of the central bent portion into an arc shape having an angle of 180 degrees or more, and it is necessary to use a substantially U-shaped slider spring.

As disclosed in Japanese Patent Application Laid-Open No. Sho 61-239473, it has been proposed to curl at least one end of a leaf spring into a cylindrical shape. The invention prevents the leaf springs from overlapping with each other by curling the ends of the flat bottom flat leaf springs as shown in FIG. 9 into a cylindrical shape.
However, although a flat bottom leaf spring having a shallow bottom has a certain effect in preventing the leaf spring from hugging and overlapping, even if the end of a substantially U-shaped slider spring having a deep bottom is curled into a cylindrical shape, The slider spring 88 shown in FIG.
The portions indicated by C and D near the straight lines a and 94b came into contact with another slider spring 88 ', and so-called hugging and overlapping still occurred.

As described above, if a plurality of slider springs are supplied to the assembling apparatus while being attached or superimposed, it may cause a defect such as a product defect or a device failure. In particular, once an overlap occurs, a separator (balancing machine) can be used to separate the overlapped slider springs.
However, in many cases, the separation is difficult, and the separation is performed only by a manual method, which is inefficient in an automated production line.

Accordingly, the present invention solves the above-mentioned problems, and a plurality of leaf springs hardly overlap each other during transport, storage or automatic assembling, and there is almost no cling.
It is an object of the present invention to provide a leaf spring that can easily remove the overlap even when a part thereof overlaps, and that maintains the urging force within a certain range.

[0013]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a center bending portion, an arm extending in a substantially C-shape on both left and right sides of the center bending portion, and the arm portion. A substantially U-shaped leaf spring having a bent portion that is bent and connected to both ends of the leg portion, and a leg portion that extends from the bent portion and has a curved portion whose end is bent outward. Is on a plane passing through the starting end of the leg or on a plane parallel to a plane perpendicular to a plane including the substantially U-shaped leaf spring and on a geometric center line of the substantially U-shaped leaf spring. It is intended to provide a leaf spring characterized in that the leaf spring is configured to be further outside.

Here, it is preferable that the curved portion of the leaf spring slides while making line contact with one plane perpendicular to the center plane, and the bent portion of the leg portion is Preferably, the arm is bent inward with respect to the arm.

Hereinafter, the leaf spring of the present invention will be described in detail.

A leaf spring according to the present invention comprises a center bent portion, an arm extending in a substantially C-shape on both left and right sides of the center bent portion, and a bent portion connected to both ends of the arm by bending. And a leg portion extending from the bent portion and having a curved portion having a distal end curved outward. This leaf spring fixes the central bent portion, abuts the leg portion on the biased component, and is disposed at any portion requiring the biasing force as long as the portion applies the biasing force to the biased component. , Can be used as parts for obtaining the required urging force. In particular, it is effective as a component used in a part where the urging force is required to be generated within a predetermined range. For example, in a magnetic tape cassette, it is useful as a slider spring mounted on the center front edge of the lower half to urge the slider forward.

Further, in the leaf spring of the present invention, the shape of the central bent portion, the length of the arm portion, and the angle formed by the left and right arm portions,
The material is appropriately determined in accordance with the required urging force, the form of the arrangement location, the installation space, the form of the assembly jig, and the like. The central bent portion is not particularly limited as long as it has a shape in which the arm portion extends in a substantially C-shape on both left and right sides. For example, the shape may be an arcuate cross section or a U-shaped cross section.

Further, in the leaf spring of the present invention, the leg portion has a function of slidingly contacting a contact portion provided on the biased component. The slidable portion does not have burrs or the like so that the slidable portion does not rub against the abutted portion of the part to be urged. It is desirable because there is no occurrence.

The material of the leaf spring of the present invention is appropriately selected according to the use, the environment of the part to be used, the required urging force, the stroke (displacement amount) and the like. In particular, when the leaf spring of the present invention is used as a slider spring of a magnetic tape cassette, in order to obtain a stable operation of sliding and retreating the slider of the magnetic tape cassette, the slider retreats and slides forward. Accordingly, it is required that the slider be largely bent and deformed, and that a predetermined urging force be stably exerted in a large stroke range in which the slider slides. For this reason, ordinary stainless steel materials cannot sufficiently meet these requirements. In particular, precipitation hardening SU
Steel strips such as S631 and SUS301 are preferred.

The thickness of the leaf spring of the present invention depends on the required characteristics, space at the place of arrangement, stroke (displacement amount),
It is appropriately determined according to the urging force and the like. In particular, when the leaf spring of the present invention is used as a slider spring of a magnetic tape cassette, the characteristics vary greatly even with a very small difference in thickness, so that the required characteristics can be sufficiently satisfied. .2 mm, preferably 0.09 to 0.2 mm.
One having a thickness of 11 mm is used.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As a specific example of the leaf spring of the present invention, a slider spring of a magnetic cassette will be described below in detail.

FIG. 1A is a plan view showing a specific example in which the leaf spring of the present invention is applied to a slider spring having a substantially U-shape used for a magnetic cassette tape. The slider spring 1 shown in FIG. 1A is a leaf spring having a constant plate width like the slider spring 56. In the plan view shown in FIG. , Its central bend 3
Arms 5a and 5b extending in a substantially C-shape on both left and right sides of
And legs 7a arranged at both ends of arms 5a and 5b
And 7b. Legs 7a and 7b
Are composed of bent portions 13a and 13b extending in a substantially C shape and connected to both ends of the arm portions 5a and 5b, and bent portions 15a and 15b bent outward.

Next, the initial shape of the slider spring 1 in which no urging force is generated will be described in detail. In the plan view of the slider spring 1 shown in FIG. 1A, the shape of the central bent portion 3 is an arc shape, and the shapes of the arms 5a and 5b extending in a substantially C shape are linear, Legs 7a and 7b
Of the bent portions 13a and 13b are linear shapes,
The curved portions 15a and 15b have an arc shape. That is, the arc shape of the central bent portion 3 is smoothly connected to the linear shapes of the arms 5a and 5b toward the distal end,
It is extended in a substantially C-shape to the bending start ends 11a and 11b, and further bent inward to the extent that the extending direction does not face inward, and is connected to the linear shapes of the bent portions 13a and 13b. Beyond the curved parts 15a and 15
It is smoothly connected to the arc shape of b. Here the inside is
As going from the central bent portion 3 to the curved portions 15a and 15b, a substantially U-shaped center line c- shown in FIG.
It refers to the direction approaching c '. The term “outside” refers to a direction away from the substantially U-shaped center line cc ′ shown in FIG. 1 (a) as going from the bending start ends 11a and 11b to the curved portions 15a and 15b.

Such a slider spring 1 is assembled to a slider spring engaging portion 86 shown in FIG. 3, and when a magnetic tape is used, the slider 7 retreats and the legs 7
a and 7b slide outward on the contact wall 80, respectively, and open so that the angle between the arms 5a and 5b increases. When the slider 54 slides forward, the slider 54
In the direction toward the inside end of the front lid 60.
FIG. 1B shows that the left and right curved portions 15a and 15b of the slider spring 1 come into line contact with the contact wall 80 and slide outward, respectively, so that the angle between the two arm portions 5a and 5b increases. It shows a state in which The slider spring 1 makes line contact with the contact wall 80 at the curved portions 15a and 15b of the legs 7a and 7b (represented as point contact in the plan view of FIG. 1B), and the two arms 5a and 5b. No surface contact with any part. The reason is that at the bending start ends 11a and 11b, the bending portions 13a and 13b are bent inward from the arms 5a and 5b within a range that does not face inward, so that the bending portions 13a and 13b are bent. Part 15
a and 15b are integrally formed to form projections D and D 'when viewed from the arms 5a and 5b, respectively, when the arms D and D' are opened when the arms 5a and 5b are opened to the left and right. However, this is because it makes line contact with the contact wall 80. That is, the protrusions D and D ′ are in
It abuts at a point, slides left and right, and applies an urging force. As a result, the arms 5a and 5b do not make surface contact,
The substantial length of the portion having the spring action does not decrease, and as a result, the repulsive force of the slide spring 1 does not increase. It does not exceed it.

The projections D and D 'are different from the conventional projections in that the bent portion 13
a and 13b are bent inward from the arms 5a and 5b, but are bent in a range that does not face inward, so that a substantially U-shaped inward convex protrusion is not formed. Nevertheless, when the legs 7a and 7b slide left and right to open the arms 5a and 5b, the contact wall 80
It exerts the function of sliding in line contact with. By utilizing the projections D and D ', the urging force of the leaf spring is prevented from increasing outside an appropriate range due to a sudden increase in the urging force, and the occurrence of the previously described difficulties of holding and overlapping described below is prevented. Therefore, even if the slider springs overlap, the overlapping slider springs can be easily separated.

The slider spring 1 has both bent portions 13a and 13b bent at the bending start ends 11a and 11b inward with respect to the arms 5a and 5b.
The bending direction is the bending portions 13a and 13b and the bending portion 1
The legs 7a and 7b including 5a and 15b are on the geometric center line of the substantially U-shaped leaf spring 1 and are perpendicular to the plane including the substantially U-shaped leaf spring 1, that is, substantially U-shaped. A plane passing through the bending start ends 11a and 11b (the plane shown in FIG. 1A), which is parallel to the center plane of the plate-shaped leaf spring (in the plan view of FIG. 1A, the center line cc 'is shown). In the figure,
Line dd 'and line ee' are shown. ) Is configured to be on or outside of this plane. in this way,
A plane passing through the bending start ends 11a and 11b (FIG. 1A)
In the plan view of FIG. 5, lines dd ′ and ee ′ are shown. The reason for configuring the legs 7a and 7b of the slider spring 1 so as to be above or outside this plane is to prevent the slider spring 1 from being hugged or overlapped, and to easily prevent the slider spring 1 from being hugged or overlapped. This is in order to be able to separate them one by one by a separator (balancing machine). That is, as shown in FIG. 2, when the slider springs 1 and 1 ′ embrace each other, the slider springs 1 and 1 ′ come into contact with each other at the portions A and B, but the contact portions are open outward. Bending part 13
a and 13b, the slider spring 1 'with the clinging is moved from the slider spring 1 in the direction F shown in FIG.
They can be easily separated. In addition, the bent portions 13a and 13a where the slider springs 1 and 1 'come into contact with each other.
The bent portion 13 is arranged so that the extending direction of the
a and 13b, even if the slider springs 1 and 1 'overlap at the A and B portions of the bent portions 13a and 13b, the center bent portion 3 to the bent portion 13
The height to the contact portion of a and 13b is not constrained by each other's slider springs 1 or 1 ', and therefore the slider springs 1 and 1' do not urge each other with a strong force, and as a result The slider spring 1 'can be easily pulled apart in the front or rear direction (the front-rear direction) shown in FIG.

On the other hand, as shown in FIG. 7, when the conventional slider spring 88 is hugged, the arms 94a and 9b are bent because the bent portions 92a and 92b face inward.
Bent portion 92a facing inward from contact portions C and D of 4b
And 92b are constrained by another embraced slider spring 88 'so that a strong biasing force is generated at the contact portions A, B, C and D of the slider spring 88. Therefore, the slider spring 88 is moved
It is difficult to separate the paper in the front or rear direction (front-back direction) shown in FIG. Further, since the bent portions 92a and 92b having the contact portions face inward, it is not easy to separate the slider spring 88 'downward in FIG.

In this embodiment, the bending start ends 11a and 11b of the slider spring 1 are
The positions of the bending start ends 11a and 11b are appropriately changed according to various characteristics such as the required strength of the slider spring and the movable range. is there. In the present embodiment, FIG.
2A, both arm portions 5a and 5a of the slider spring 1 are shown.
The shape of b and the shapes of the bent portions 13a and 13b are all configured as a single linear shape, but are not limited thereto, and may be an arc shape, or a combination of a plurality of linear shapes or arc shapes. .

[0029]

As described above in detail, in the leaf spring of the present invention, the substantial length of the portion having the spring action is reduced, the repulsive force of the spring is increased, and the urging force is rapidly increased. A projection that has been used in the past to prevent this, that is, a projection that forms a generally U-shaped inwardly convex shape in the initial shape, and is abutted even when both arms of the leaf spring are greatly opened. Without having a projection that makes line contact with the wall, it is possible to apply a constant urging force by making line contact with the contact wall in the same manner as a conventionally used projection, and at the time of occurrence of the The separation of the leaf springs and the overlapping leaf springs by the separator can be easily performed one by one by a separator (balancing machine) without manual operation, and the production efficiency can be improved.

[Brief description of the drawings]

FIG. 1A is a plan view of an example of a slider spring which is a specific example of the leaf spring of the present invention, and FIG. 1B is a diagram showing the slider spring that opens both arms and contacts a contact wall. It is a top view which shows a mode that it does.

FIG. 2 is a view for explaining holding of a slider spring which is a specific example of the leaf spring of the present invention.

FIG. 3 is a diagram illustrating a main configuration example of a magnetic cassette tape and illustrating incorporation of a slider spring.

FIG. 4 is a diagram illustrating an example of a main configuration of a magnetic cassette tape and illustrating incorporation of a slider spring.

FIG. 5 is a perspective view illustrating the structure of a conventional slider spring.

FIG. 6 is a plan view showing a state in which a conventional slider spring opens both arms and comes into contact with a contact wall.

FIG. 7 is a view for explaining holding in a conventional slider spring.

FIG. 8A is a diagram illustrating an example of a state of conveyance of a conventional slider spring, and FIG. 8B is a diagram illustrating holding and overlapping of the slider spring during conveyance.

FIG. 9 is a diagram illustrating a conventional leaf spring that prevents hugging and overlapping.

FIG. 10 is a diagram illustrating a conventional leaf spring that prevents hugging and overlapping.

[Explanation of symbols]

 1, 1 'slider spring 3 central bending portion 5a, 5b arm portion 7a, 7b leg portion 11a, 11b bending start end 13a, 13b bending portion 15a, 15b bending portion 50 upper half 52 lower half 54 slider 56 slider spring 60 front lid 72 Central bent portion 74a, 74b Arm portion 76a, 76b Leg portion 78 Slider spring retaining portion 80 Contact wall 82a, 82b Sliding contact portion 84 Lower half 86 Slider spring retaining portion 88, 88 'Leaf spring 90a, 90b Leg portion 92a, 92b Bend 94a, 94b Arm D, D 'Projection

Claims (1)

[Claims] 1. A central bent portion, an arm portion extending in a substantially C-shape on both left and right sides of the central bent portion, a bent portion bent and connected to both ends of the arm portion, and the bent portion And a leg having a curved portion with a distal end curved outwardly, the leg being disposed on a geometric center line of the substantially U-shaped leaf spring. The leaf spring is configured to be on or outside a plane passing through the starting end of the leg portion, which is parallel to a plane perpendicular to a plane including the substantially U-shaped leaf spring.